This invention relates to a combined earthquake sensor and night light of durable construction, low cost, and pleasing appearance which can serve as a visual aid in determining the occurrence of an earthquake or aftershock. The onset of an earthquake is usually quite sudden. Depending upon the distance between the particular location and the epicenter, only seconds elapse between the initial tremors and the arrival of the main shock. On the other end of the scale, there are various conditions, both real and imagined, which can trigger off the feelings of experiencing a minor earthquake when in fact none has occurred.
A number of early warning systems have been invented to signal the onset of an earthquake. Some are quite elaborate and involve placing sensors over a wide geographic area and linking them by radio with a central station. Others employ motion sensors based on a suspended magnet inducing a current in a coil or a suspended pendulum interrupting a beam of light. U.S. Pat. No. 3,091,972, issued Jun. 4, 1963 to Johnston, shows an elastically supported pendulum which interrupts a beam of light acting on a light sensitive transducer. U.S. Pat. No. 4,250,537, issued Feb. 10, 1981 to George P. Roegner et al, shows a mirrored globe suspended by a flexible support and illuminated by a source of light. Vibrations cause movement of the globe to reflect the light in different patterns.
A second desideratum of the invention is the design of a durable night light which can be placed on location in a living space to identify a particular location with sufficient emitted light. A long lasting source of light illuminates a faceted crystal globe to achieve a novel lighting effect.
A number of ornamental light fixtures have been invented as typified by U.S. Pat. No. 3,746,852, issued Jul. 17, 1973 to Mary Louise Beaudin, and U.S. Pat. No. 4,072,855, issued Feb. 7, 1978 to Ludovico Marchese. The patent to Beaudin shows a plurality of hemispherically shaped refracting and reflecting lenses mounted upon wire supports above a source of light. The patent to Marchese shows an upright transparent container filled with a fluid containing a plurality of floating reflective platelets. A source of light beneath the container is reflected by the floating platelets in different patterns.
While the above mentioned patents do teach separate motion sensors and light fixtures, the prior art does not teach a combined earthquake sensor and night light having the simplicity of construction, the reliability, and the ease of operation found in the instant invention.